Learning objectives
What you will be able to explain
- Which storage medium typically has the lowest access latency?
- Which of the following are non-volatile storage?
- The 'Memory Wall' refers to the major gap between which components?
- Locality of Access: True or False
- Cache-hit-ratio calculation
- Who primarily moves data between main memory and CPU caches?
Section 01
Which storage medium typically has the lowest access latency? to The 'Memory Wall' refers to the major gap between which components?
01
Which storage medium typically has the lowest access latency?
02
Which of the following are non-volatile storage?
Guided checkpoint
Select all that apply.
03
The 'Memory Wall' refers to the major gap between which components?
Section 02
Locality of Access: True or False to Who primarily moves data between main memory and CPU caches?
01
Locality of Access: True or False
Guided checkpoint
Mark each statement as True or False.
02
Cache-hit-ratio calculation
Guided checkpoint
A system performs 10,000 requests. 9,500 are cache hits and 500 are misses.
cache-hit-ratio = nb_hits / (nb_hits + nb_misses)Enter the ratio as a decimal value.
03
Who primarily moves data between main memory and CPU caches?
Section 03
Which are mechanical parts of a magnetic disk assembly? to Megatron 747: disk capacity
01
Which are mechanical parts of a magnetic disk assembly?
Guided checkpoint
Select all that apply.
02
What is a cylinder in hard disk mechanics?
03
Megatron 747: disk capacity
Guided checkpoint
Compute total capacity for: 16 surfaces, 65,536 tracks/surface, 256 sectors/track, 4,096 bytes/sector.
Return the result in TB where 1 TB = 2^40 bytes.
total_bytes = surfaces * tracks * sectors * bytes_per_sectorSection 04
Can standard HDD heads typically read different surfaces in parallel? to What is the usual assumption for average rotational latency?
01
Can standard HDD heads typically read different surfaces in parallel?
02
Rotational latency: full rotation time
Guided checkpoint
A disk rotates at 7,200 RPM. Compute the time for one full rotation in milliseconds.
rotations_per_second = 7200 / 60
time_per_rotation = 1 / rotations_per_second03
What is the usual assumption for average rotational latency?
Section 05
Average Seek Time Calculation to What is the core assumption of the I/O model for DB analysis?
01
Average Seek Time Calculation
Guided checkpoint
Using the Megatron 747 model, assume seek time is defined as 1 ms + (tracks_travelled / 4000) ms.
If the disk has 65,536 tracks and the average seek distance is 1/3 of the tracks, calculate the average seek time.
02
What is required to modify a disk block?
03
What is the core assumption of the I/O model for DB analysis?
Section 06
Which techniques can reduce disk access time or improve throughput? to Match disk failure types
01
Which techniques can reduce disk access time or improve throughput?
Guided checkpoint
Select all that apply.
02
Average case disk latency
Guided checkpoint
Compute latency to read a 16 KB block with: seek = 6.46 ms, rotational = 4.17 ms, transfer = 0.13 ms.
latency = seek + rotational + transfer03
Match disk failure types
Guided checkpoint
Match each failure type to the correct description.
Section 07
If you use independent parity bits for a sector, what is the probability that an error will NOT be detected? to Match RAID levels to their characteristics
01
If you use independent parity bits for a sector, what is the probability that an error will NOT be detected?
02
In the `Stable Storage` writing protocol, why is data stored in two sectors (XL and XR)?
03
Match RAID levels to their characteristics
Section 08
Which RAID levels protect against at least one disk failure? to What is the minimum number of disks required for RAID 6?
01
Which RAID levels protect against at least one disk failure?
Guided checkpoint
Select all that apply.
02
RAID 5 storage efficiency
Guided checkpoint
A RAID 5 array has 5 identical disks. Compute storage efficiency in percent.
efficiency = (N - 1) / N03
What is the minimum number of disks required for RAID 6?
Section 09
Main advantage of RAID 5 over RAID 4? to MTTDL for system without RAID
01
Main advantage of RAID 5 over RAID 4?
02
What does MTTF represent for a disk?
03
MTTDL for system without RAID
Guided checkpoint
System has 100 disks. Each disk MTTF is 50,000 hours. With no RAID, any disk failure causes data loss.
MTTDL = MTTF_per_disk / N_disksSection 10
Why do DBMSs often use their own memory management? to Best use case for tertiary storage (e.g., magnetic tape)?
01
Why do DBMSs often use their own memory management?
02
SSD properties: True or False
Guided checkpoint
Mark each statement as True or False.
03
Best use case for tertiary storage (e.g., magnetic tape)?
Knowledge check
Turn understanding into recall.
The quiz now follows the same concepts in scored form. You can return to this lesson from the quiz whenever a gap appears.